Conventional heat assisted magnetic recording (HAMR) utilizes a laser in a conjunction with magnetic recording technology to write to magnetic media in a disk drive. Light is provided from a laser to a waveguide in a HAMR transducer fabricated on a slider. The light travels through the waveguide toward the air-bearing surface (ABS) and is coupled into a near-field transducer (NFT) via evanescent coupling. Thus, the exponential tail of the waveguide mode in the cladding of the waveguide may excite the plasmons in the NFT. Through these plasmons, the NFT couples light into the media at a spot size smaller than the optical diffraction limit, heating a region of the media. Coils in the transducer energize the main pole to magnetically write to a portion of the media heated by the spot size at a relatively modest field. Thus, data may be written to the media.
In order to obtain the desired performance, lifetime and reliability of the HAMR transducer, various factors are desired to be optimized. For extended laser and NFT lifetime, a high coupling efficiency is desired between the optical components. For example, optical coupling from the laser to the waveguide and from the waveguide to the NFT are desired to be improved. In addition, leakage of light from the components is desired to be small. For example, leakage of light from the waveguide to the media is undesirable because such leakage adversely affects writing performance and may degrade adjacent tracks. The laser power is also desired to be stable, both for improved writing efficiency and for laser lifetime. Other factors may also contribute to the performance and reliability of the HAMR writer. Thus, continued improvements in the HAMR transducer are desired.